Head structure for internal combustion engines



y 1937. c. B. JAHNKE 2,080,720

HEAD STRUCTURE FOR INTERNAL COMBUSTION ENGINES Filed Feb. 15. 1933 INVENTOR.

18 ATTORNEY.

Patented May 18, 1937 F Fl-CE HEAD STRUCTURE FOR INTERNAL COMBUSTION ENGINES Charles B. Jahnke, Oak Park, Ill., assignor to Fairbanks, Morse & 00.,Chicago, 111., a corporation of illinois Application February 13, 1933, Serial No. 656,473

3 Claims.

This invention relates to improvements in head structures for lntemal combustion engines, and more particularly to an improved arrangement and construction of combustion chambers in engines of the compression-ignition type.

An object of the present invention is to pro-- vide an internal combustion engine with an improved combustion chamber of such form that the degree of turbulence and mimng of the fuel and air may be readily and easily altered so that efiicient combustion will be obtained for all operating conditions of the engine.

A further object is attained in an engine of the compression-ignition type, in an improved means for varying the operative clearance volume of the engine during the starting period, such that the compression pressure is increased sufliciently to insure ignition of the charge when the engine is cold.

A still further object is attained in an engine of the compression-ignition type, in an improved arrangement and construction of combustion space, in which a plurality of chambers collectively constituting the engine clearance space, are in fluid communication bymeans of a passage which is arranged so as to obtain turbulence and thorough mixing of thefuel charge and air within the combustion space.

An additional object is to provide an engine of the solid fuel injection type, with an improved means for varying, within limits, the volume of the combustion space for purposes of increasing or decreasing the compression temperature of the engine, either during its starting onnormal running period, the volume-varying means being controllable from the exterior of the engine without removal of the cylinder head.

Still further objects and advantages will appear from the following detailed description of parts and the accompanying drawing, in which:

Fig. l is a sectional elevation of a preferred form of internal combustion engine; Fig. 2 is a section taken along line 2'2 of Fig. 1; Fig. 3 is a transverse section through the cylinder head, as viewed along line 3-3 of Fig. 1, and Fig. 4 is a fragmentary section in the plane of Fig. 2, but illustrating a modified form of discharge passage from the combustion chamber to the cylinder clearance.

Referring by reference characters to the drawing, the numeral 10 designates, generally, a preferred form of internal combustion engine of the solid fuel-injection type, and is shown as provided with a cylinder H, in which operates a piston l2. A cylinder head 13 is secured to the cylinder H, the inner surface of the head being by preference shaped to conform to the head portion of the piston, which in the present example is formed with curved baflieportions l4. Only sufficient clearance space 15 remains between the cylinder head and piston top, as is mechanically permissible. This clearance space is, by preference in fluid'communication by means of a passage IS with a combustion chamber l'i, disposed within the cylinder head l3. This combustion chamber is, by preference, cylindrical in form with its axis disposed at a right angle to the centerline of the cylinder H.

In Figs. 1 and 2 the passage 16, directed tangentially from the combustion chamber [1, is shown as being of circular section. A modification of this arrangement is shown in Fig. 4 illustrating, in the plane of Fig. 2, only a fragmentary portion of the chamber structure in connection with which there is provided apassage 30, also arranged tangentially of the cylindrical portion of the chamber and being in all important respects the same as passage I6, heretofore described, except as being of a distinctly oval or oblong cross-section, the major axis of the oblong section being disposed parallel to the axis of the chamber H. The oblong or oval passage 30 is regarded as conducing to somewhat better engine operation under heavy duty service.

To obtain a high degree of turbulence within the combustion chamber H, the passage It (or 30) is arranged tangentially of the cylindrical portion of ,the chamber, the axis of the passage being, by preference, parallel to, but somewhat ofiset from the centerline or axis of the cylinder, and is located intermediate the ends of the combustion chamber, when adjusted ,to its usual running volume. In addition, this passage IE (or 30) is, by preference, provided with a flared or conical outlet portion I8, the base of the cone being substantially flush with the inner surface of the cylinder head. Such an arrangement of the passage 56 (or 30) with respect to the cylinder and combustion chamber, insures thorough mixture of the fuel charge and efficient combustion. A fuel injection nozzle I9 is, by preference, arranged at the end of the combustion chamber H, the centerline of the nozzle being parallel to the axis of the cylindrical chamber ll, but outwardly offset from such axis, being preferably arranged substantially along the periphery of the chamber. Such an arrangement aids in bringing the sprayed fuel into the path of the whirling air in the chamber |1,'to insure a thorough mixing action of the fuel and air.

The combustion chamber I1 is variable in length between limits, the variation in length, and hence in volume, being provided for by means of a plunger or piston 20 which is operable within the chamber by means of a manual control arm 2!, securely attached to a threaded rod 22. This rod is, by preference, rotatably secured to a slotted socket portion 23 formed on the outer end of plunger 20, so that the rod may be manually rotated for moving the plunger endwise of the chamber l1, without rotating the plunger. The threaded portion of the rod 22 engages an internally threaded portion 24, provided in a gland member 25 which is removably and adjustably attached to the cylinder head, as by cap screws 26. A suitable packing sleeve such as 21, is arranged between the gland member 25 and the plunger, for insuring a fluid tight connection therebetween. Fluid-pressure sealing rings 28 are provided on the plunger 20 to confine the pressure of .the Dre-combustion chamber substantially ahead of the piston 20. It will be apparent that by moving the plunger 20 within the cylindrical combustion chamber, the chamber volume may be increased or decreased in accordance with operating conditions of the engine.

- For engines subjected to a substantial variation in speed and other operating conditions, the manual control of arm 2|, as heretofore described, is to be preferred. In engines operating under conditions where it is desired to effect as complete a control as possible by a speed responsive agency, a governor of any usual or suitable form (not shown) may be connected for control purposes through any usual linkage to the lever 2|, in which case the threaded shank of the shaft 22 would be provided with threads of somewhat greater pitch so as to result in a full range of displacement of the piston 20 conformably to the available range of governor control movement.

For cooling the combustion chamber, passage 16, the fuel injection nozzle, plunger 20 and associated parts, a water jacket 29 is provided in the cylinder head I3, which, as shown, substantially completely surrounds the chamber I1.

It has been found from experience that in starting cold engines of the compression-ignition type, it is desirable to increase sufficiently the compression in the combustion chamber and associated passage, to insure an ignition temperature of the fuel charge. In the present arrangement, this is accomplished by reducing the volume of the combustion chamber by means of the plunger 20, which is, at starting, moved inwardly of the chamber through the agency of the manual control arm 2i. It will be apparent that during the inward movement of the piston l2 within the cylinder II, the air trapped inthe cylinder is compressed and forced through the passage l6 into the combustion chamber l1. Since the passage I6 is tangential of the chamber, a turbulent, whirling action is set up in the chamber. This turbulent action is most effective during the injection period, and hence thorough mixing of the compressed air and the injected fuel is obtained, which results in eflicient combustion. A distinct advantage is. noted, in that the fuel is injected near the'periphery of the chamber l1, into the path-of the strata of whirling air of uniform and greatest velocity, to in- .sure a thorough mixing of the charge with the air. It will appear as a further advantage that the fuel stream is of a trend at about a right angle to the direction of movement of the tur- 15 through passage I 6. After the engine is running, or in response to an increase in load thereon, the plunger 20 may be moved to increase the volume of the combustion chamber, for obtain-' ing more efficient running conditions.

It has been found from experience that often during the'idling period of an engine, the walls of the cylinder, piston, combustion chamber and other associated portions will have sufficiently cooled to cause incomplete combustionand often, particularly in the case of smaller engines, the engine will stop as aresult. This condition may be remedied by manually controlling the volume of the combustion chamber by means of the arm 2| and the associated plunger 30. Such a manipulation will increase the compression pressure to a point to insure ignition of the fuel charge, during the idling period of the engine. It is entirely possible, by virtue of the limited range of movement of piston 20, to effect such a setting, and thereafter to maintain the same setting during the normal running of the engine, without any hazard or appreciable harmful effects.

With the present, improved arrangement, the operating clearance volume of the engine may be readily and easily adjusted at starting, or to correspond with any running condition of the engine,

' without removal of the cylinder head. The present arrangement is simple and sturdy in construction, and in use effectively controls the turbulence and mixing of the fuel spray with the air to insure complete and efllcient combustion of the fuel, and hence permits of maximum fuel economy.

It will, of course, be understood that the present disclosure relates only to a single preferred executional embodiment of the invention, and'that substantial changes may be made in the described exemplary construction and arrangement of parts, without departing from the spirit and full intended scope of the invention.

I claim as my invention:

1. In an internal combustion engine, a head structure forming a combustion chamber of cylindrical form, a cylinder and a piston operating within said cylinder with a minimum clearance between the piston and the head structure, a restricted passage providing fluid communication between said combustion chamber and clearance, said passage being arranged tangentially of the cylindrical portion of the chamber, a fuel injec-. tion nozzle arranged at the end of the combustion chamber, the axis of the nozzle being parallel to the axis of the chamber, but outwardly offset from the chamber axis, a plunger having limited,

a restricted passage providing fluid communlcation between said combustion chamber and clearance, said passage being-arranged tangentially of the cylindrical portion of the chamber, a fuel injection nozzle arranged at the end of the combustion chamber, the axis of the nozzle being parallel to the axis of the chamber, but outwardly offset from the chamber axis, a plunger movably disposed in said chamber for varying the volume thereof, stop elements establishing limits of adjusted placement of said plunger, and means operatively associated with said plunger, and extending to the exterior of the head structure, for selectively positioning said plunger within said combustion chamber.

3. In an internal combustion engine, a head structure forming a combustion chamber of cylindrical form and a cooling fluid jacket substantially enclosing the combustion chamber, a power cylinder and a piston operating within said cylinder with a minimum clearance between the piston and the head structure, the combustion chamber being arranged with its axis crosswise of and intersecting the power cylinder axis, a restricted passage providing fluid communication between said combustion chamber and clearance, said passage being arranged tangentially of the cylindrical portion of the chamber, and elongated in a direction axially of the chamber, a fuel injection nozzle arranged at the end of the combustion chamber, the axis of the nozzle being parallel to the axis of the chamber, but ofiset from the chamber axis, a plunger arranged in a portion of the combustion chamber opposite said fuel injection nozzle and having limited movement in said chamber for varying the volume thereof, and means operatively associated with said plunger, and extending to the exterior of the head structure, for selectively positioning said plunger within said combustion chamber.

CHARLES B. JAHNKE. 

